MORPHOLOGY AND EVOLUTION
•28. The cribriform plate of the ethmoid bone-is not so
high above the foramen magnum, 24. The greatest longitudinal diameter of the cranial
cavity runs between the glabella and the internal
occipital eminence; in man it runs to a point
above the eminence. *25. The cribriform plate of the ethmoid is level with the
lower part of the orbit; in Man it is level with
the middle of the orbit. •26. The nasal cavities are relatively longer.
27. The plane of the floor of the nose is parallel to the
lower border of the basi-sphenoid and basi-occipital; in Man it forms an angle of forty-five degrees with them.
28. A line drawn back along the cribriform plate to the
posterior clinoid processes in Man makes an angle of ninety-five degrees with one drawn on the cranial surfaces of the basi-occiput and basi-sphenoid. In the Gorilla the angle is described as ISO-.
29. There is a simian shelf on the mandible.*
VERTEBRAL COLUMN, PELVIS, STERNUM A
The vertebral column in the Apes differs from that in Man in its curvatures, in the characters of some of the bones, and in the number of rib-bearing elements. Its axis is never absolutely vertical as in Man, but it is oblique even when the Ape is erect.
In all Apes there are seven cervical vertebrae with capacious vertebral foramina. The spinous processes are long, and their free extremities are sometimes expanded. In Man some of the spinous processes are bifid, but the only approach to this in the Apes is the presence of two
* The Piltdowii skull (Eoanthropw) has a marked simian shelf, f The axial skeleton is described in papers 20, 25, 39, 40, 44, 55- 59< 122, 162, 188, 253, 269, 276. 461, 473, 494.